MyInspectCamera

using UnityEngine;
using System.Collections;
public class MyInspectCamera : MonoBehaviour {
    public Transform target;
    public Transform CamTransform;
    public float distance = 10.0f;
    public float minDistance = 2;
    public float maxDistance = 20;
    public float xSpeed = 250.0f;
    public float ySpeed = 120.0f;
    public float yMinLimit = 2f;
    public float yMaxLimit = 80.0f;
    private float x = 23.0f;  //初始时候的欧拉角， 随便设ge
    private float y = 6.0f;
    public float zoomInLimit = 2.0f;
    public float zoomOutLimit = 1.0f;
    public float yOffset = 0; //目标在屏幕上Y坐标的偏移
    public LayerMask ignoreLayer; //射线检测要忽略的层
    private float lastClearTime;  //记录上次没遮挡的时间
    void Start()
    {
        Vector3 dir = (CamTransform.position-target.position  ).normalized;
        CamTransform.position = dir * distance + target.position;
        CamTransform.LookAt(target.position);
        Vector3 angles = CamTransform.eulerAngles;
        x = angles.y;
        y = angles.x;
   
        if (target == null)
            target = GameObject.FindGameObjectWithTag("Player").transform;
        if (CamTransform == null)
            CamTransform = transform; // 这个主要 是给摄像机使用的
    }
    void LateUpdate()
    {
        if (Input.GetMouseButton(1))  //按下右键才旋转视角
        {
            x += Input.GetAxis("Mouse X") * xSpeed * 0.02f;
            y -= Input.GetAxis("Mouse Y") * ySpeed * 0.02f;
            y = ClampAngle(y, yMinLimit, yMaxLimit);
        }
        Quaternion rotation = Quaternion.Euler(y, x, 0);
        Vector3 TargetPos = rotation * new Vector3(0.0f, yOffset, -distance) + target.position;
        CamTransform.rotation = rotation;
        RaycastHit castInfo;
        LayerMask mask=~(ignoreLayer);
        Debug.DrawLine(target.position, TargetPos, Color.red);
       if (Physics.Linecast(target.position, TargetPos, out castInfo,mask)) //在摄像机当前坐标和目标点之间进行障碍物检测， 要是中间有障碍物就，只移动到离障碍物稍偏一点位置
       {
          // if (Time.time - lastClearTime > 0.5f) //遮挡超过一定时间才跳
           {
               Vector3 dir = (TargetPos - CamTransform.position).normalized;
               Vector3 targerPoint = castInfo.point - dir * 0.5f;
               CamTransform.position = Vector3.Lerp(CamTransform.position, targerPoint,Time.deltaTime*3);
           }    
        }
        else
       {
            CamTransform.position = TargetPos;
            lastClearTime = Time.time;
        }
        #region 滚轮缩放
       float scrollValue = Input.GetAxis("Mouse ScrollWheel");
        //拉近距离的方式
       if (scrollValue != 0)
       {
           distance -= scrollValue;
           distance = Mathf.Clamp(distance, minDistance, maxDistance);
       }
        #endregion 滚轮缩放
                      
      
    }
   
    static float ClampAngle(float angle, float min, float max)
    {
        if (angle < -360.0f)
            angle += 360.0f;
        if (angle > 360.0f)
            angle -= 360.0f;
        return Mathf.Clamp(angle, min, max);
    }
}